As an example of a display device which displays an image in the air, an imaging device whereby display light, which is first polarized light, emitted from a display module is regularly reflected by a reflective polarizing filter, the light is changed into second polarized light and retroreflected by a retroreflective portion, the retroreflected light passes through the polarizing filter, and an image is formed at a position symmetrical to the display module with respect to the polarizing filter, is disclosed.
When the retroreflective portion is constituted of a plurality of reflector plates, the retroreflective properties may be degraded at each joint between the reflector plates.